Environmental Systems

Ronn Phillips, Arch.D., and Bobbi
Hauptmann, Architectural Studies, College of Human
Environmental Sciences, University of Missouri-Columbia

Environmental systems are the mechanical systems in a house
that are required to support human activities. Knowledge about
what these systems are and how they operate is important to
every homeowner.

Plumbing Systems: Residential plumbing systems can
be divided into two types: (a) water supply, and (b) waste
drainage. Supply lines may be of copper, galvanized steel, or
plastic, with copper being the most prevalent. The sanitary
drainage system relies on gravity for its discharge; its pipes
are much larger than the water supply lines, which are under
pressure. Drainage lines may be of cast iron or plastic.

Heating, Ventilating, and Air-Conditioning (HVAC):
system selection should consider the following issues:

Performance, efficiency, and the initial and life costs
of the system

Fuel, power, air, and water required

System flexibility to service different zones of the
house

Space requirements for the mechanical equipment and
distribution system

Access required for service and maintenance

Degree of visibility, whether concealed within the
construction or exposed to view

Thermal Insulation: The following types of
insulation are common:

Rock Wool - blanket form and most common before 1950.

Fiberglas - most common since 1950; more resilient than
rock wool.

Cellulose - made from scrap paper products.

Perlite - A loose material usually used to fill voids;
inorganic, noncombustible and moisture and insect resistant.

Polystyrene Form - Usually in pellet form or as
bead-board; inorganic polymer that is combustible but decay,
moisture, and insect resistant.

Polyurethane & Polylsocyanaurate Foam - Usually in rigid
board form; formable and subject to dimensional changes due
to curing and aging.

Formaldehyde Foam - Inorganic foam pumped into wall
cavities most common as a retrofit on older homes.

Electrical Systems: One hundred percent copper
wiring is ideal wiring material for home construction. Special
electrical receptacles -- ground fault interrupters (GFI) --
are placed in all bathrooms and on the home's exterior. The
GFI trips the breaker in 1/200 of a second to ensure instant
and total safety in case of an accident (i.e., a dropped
hairdryer or electric shaver in a sink of water).

Providing Electric Service: the service connection
to your home may be overhead or underground. Overhead service
is less expensive, easily accessible for maintenance, and can
carry high voltages over long runs. Underground service is
more expensive but is frequently used in high-density urban
areas. The service cables are run in pipe conduit or raceways
for protection and to allow for future replacement. Direct
burial cable may be used for residential connections.